The recovery of plastics from waste streams such as durable goods is a considerable challenge due to the presence of several types of plastics as well as non-plastics contaminants. The initial stage in the plastic recovery process when the durable goods are waste electrical and electronic equipment (WEEE) is the creation of electronics shredder residue (ESR). ESR is the plastic-rich mixture available after the metal recycling company has shredded the WEEE and removed the majority of the metals from the shredded mixture. The ESR can then be processed to recover acrylonitrile-butadiene-styrene (ABS), high impact polystyrene (HIPS) and polypropylene (PP) plastics.
Metal recycling companies tend to produce smaller amounts of ESR, though, so the ESR material is often transported from several metal recyclers to a single plastics recovery and purification facility. Much of the value added at the plastics recovery and purification facility is from the purification of the ABS, HIPS and PP, so it is economically favorable if the feed to the plastics recovery and purification facility is primarily ABS, HIPS and PP.
A number of processes and process combinations may enable the creation of a mixture with a high concentration of target plastics (ABS, HIPS and PP) from ESR, but it would be beneficial to use an approach that also creates several other products that are created to maximize the overall value of all products.